DURHAM, N.C.—With two-tenths of a second remaining against Ohio State and his Duke Blue Devils comfortably in the lead, senior big man Mason Plumlee had an opportunity to showcase his most improved skill.

As he toed the free-throw line and squared up his shoulders, Plumlee stood before the frenzied capacity crowd at Cameron Indoor Stadium as, almost unbelievably, a reliable free-throw shooter. This, from a future NBA lottery pick who shot 54.3 percent from the foul line as a freshman, 44.1 percent as a sophomore and 52.8 as a junior.

At the ACC media day in October, Plumlee promised anyone who asked that he’d worked tirelessly on his free-throw shooting. The other areas for improvement in his game dealt most with consistency—he would dominate for stretches offensively, and he would dominate for stretches defensively. Those stretches didn’t coincide as much as Duke fans might have wanted through his first three years, though.

The primary on-court constant of Plumlee’s game his first three years was his failing at the line. So far this season, Plumlee has delivered on his media-day promise.

“It’s just a lot of repetition, to be honest,” Plumlee said. “I can confidently say that no one, that I know of, has shot as many free throws as I did in the offseason.”

In that final second Wednesday night, with the Blue Devils beating the Buckeyes by four, Plumlee was shooting exactly 80 percent (44-of-55) for the year. On his first attempt, his newfound shooting touch was on full display—the ball hit the front of the rim softly, bounced to the back and eased through the net.

The second one didn’t go so well, to say the least. “I told coach that I started celebrating a little too early,” Plumlee said with a laugh. “Golly. I don’t know.”

The second attempt never came close to actually touching the rim. To put a positive spin on it, you could say it was all net—just the outside of the net instead of the inside. The 9,314 fans at Cameron had flashbacks, as did his teammates, coaches and everyone else associated with the program. It wasn’t pretty.

“He got that airball out of his system,” Duke coach Mike Krzyzewski joked after the game. “I told him to shoot it, get it out because it didn’t make any difference right then.

It was a lighthearted, comical capper to what was yet another impressive performance for the senior big man. Plumlee finished with 21 points—he was 6-for-11 from the field and 9-for-12 from the line—and 17 rebounds. This was his fourth double-double of the season, the third time he’s reached the 20-point plateau, and his 17 rebounds tied a career high.

There was a time he scored primarily because he was more athletic than those who were guarding him in the post, though he often had no idea how to finish once that athleticism created a good look. There was a time he committed too many silly fouls and unforced turnovers. There was a time he couldn’t be left in the game down the stretch because he was such a liability at the line.

That seems so long ago. You want a reason the Blue Devils already have wins over three top-five teams—Kentucky, Louisville and Ohio State—this season? It starts with Plumlee, who is playing like a first-team All-American and top-10 NBA draft pick. And that buys him just a tiny bit of leeway for one measly, wayward free throw.

“There’s no reason to give him trouble for that, because he played such a great game,” fellow senior Ryan Kelly said with a smile. “If he had struggled from the foul line, I might have had to have a talk with him. But it’s fine if he misses one there.”